1. Field of the Invention
This invention concerns an apparatus for cooling turbine blades, particularly turbine blades capable of functioning at a high temperature.
2. Description of the Prior Art
Cooling the blades by way of providing a structure having air circulation channels is a well-known method in which air intake takes place at the base and the discharge takes place through the tip of the blade and by way of the leading and trailing edges. Yet, it has been realized that air flow through the tip of the blade (about 80% in traditional systems) is very sensitive to clearance variations at tip end of the blades, or between the blade and the turbine ring, at least with respect to blades with low blade height. Indeed, the clearance varies considerably in transitory speed according to the models and during the life of the engine.
Therefore, the counter-pressure at the tip of the blades is not at all well-known, and it considerably affects the cooling air flow, and thus the temperature of the blade, hence resulting in concern over leading most of the air flow into an area where the counter-pressure is known, weak and constant. However, the present invention has established that an area with these characteristics exists under the blade platform on the trailing edge side.